Graphical Abstract (Angew. Chem. Int. Ed. Engl. 71995)

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A Journal of the
Gesellschaft
Deutscher Chemiker
~.______
1995
3417
International Ed tion in Engl sh
Pages 703-834
COVER PICTURE
The cover picture shows the structure of hexakis(trimethylsilylethynyl)[3]radialene, a
carbon-rich compound with unusual electronic properties. This trimethylsilyl
derivative of a C,,H, hydrocarbon, which could serve as a monomer for a twodimensional carbon network, can be prepared from readily available compounds in
only a few steps. The [3]radialene forms deep red crystals, and unexpectedly its
absorption is strongly red-shifted. Solutions of the radialene in dichloromethane are ‘
purple-red; electrochemical reduction proceeds through a rainbow of colors from
purple-red over violet to light green. F. Diederich et al. report more on this interest- .
ing compound on pages 805-809.
This issue of Angewandte Chemie serves as a launching pad for the first issue of
Chemistry- A Europeun Journal, which is bound at the back. A separate Table of
Contents at the beginning of the “Chemistry” section gives more information about
the contributions in the inaugural issue.
REVIEWS
Contents
V. Bohmer ..................................
Cyclic oligomers in which phenol or resorcinol units
are linked by inethylene or alkylidene bridges are
called calixarenes and resorcarenes, respectively.
They can be readily prepared in large quantities and
are ideal starting materials for the synthesis of a
large number of host molecules. in which these basic
structures are modified or are combined to give
larger units as in I . Potential applications of calixarenes include their use as highly specific ligands for
analytical chemistry, the decontamination of waste
water. the construction of artificial enzymes, and the
preparation of new materials.
713-745
Calixarenes. Macrocycles with (Almost)
Unlimited Possibilities
1
A hydrogen abstraction as first step is the common feature of the nonenzymatic D N A
cleavages presented here. The cleavage reagents are redox-active transition metal
complexes endowed with affinity for D N A and cytotoxic natural substances like
enediynes and bleomycins. They all attack the deoxyribose sugar unit of DNA, and
any one of the five hydrogen atoms could be abstracted. After a survey of the modes
of activation and binding to DNA, current ideas on the molecular mechanisms of the
D N A degradation by these substances are discussed.
G. Pratviel, J. Bernadou,*
B. Meunier ..._...._........__
..__..
. . . ..._.746 -769
Carbon-Hydrogen Bonds of DNA Sugar
Units as Targets for Chemical Nucleases
and Drugs
HIGHLIGHTS
Contents
A Cu-Cu bond in the mixed-valent Cu, center of cytochromec oxidase of Bacillus
subtilis was postulated last year, though with necessary caveats, on the basis of
EXAFS measurements. The deduced arrangement (bottom left) contradicts another
structural proposal (bottom right) from the same year. A critical appraisal of all
evidence available at present still suggests a negative answer to the question posed
in the title.
H. Bertagnolli,* W. Kaim” ........ 771 -773
The Dinuclear Cu, Center in Cytochrome c
Oxidase and N,O Reductase -A MetalMetal Bond in Biology?
(CYSf
‘CH,
(His)
I
/
Three total syntheses of zaragozic
acids, a new group of natural prod0 OH
ucts with blood cholesterol lowering
-C
H
O
2
properties, were successfully develF+
HOzC
oped within a short time and pubH0C02H
lished almost simultaneously. Convergence, skilled manipulation of
protecting groups, and highly stereoselective reactions are the appealing features of
these first syntheses of zaragozic acidA (Nicolaou) and zaragozic acidC (1) (Carreira and Evans).
’
U. Koert * ..................................
773-778
Total Syntheses of Zaragozic Acid
COMMUNICATIONS
The arrangement of charged and uncharged guests
(N; and two H,O molecules; see structure on the
right) and their interaction in the cavity of the anion
of the title compound 1 can be controlled by deliberately exchanging particles in the truncated cone outside the host (not shown), which resembles an ion
channel. Since 1 can incorporate a diversity of
guests, continuing studies promise exciting insights
into these interactions.
A. Miiller,* K. Hovemeier,
E. Krickemeyer, H. Bogge ......... 779-781
Crowns of thiophenes of type 2 with
five, six, and eight heterocycles were
obtained in moderate to good yields
in the reaction of the appropriate
[nlrotanes of type 1 and Na,S. In the
crystal 2 adopts a chairlike conformation with three thiophene S atoms
above and three below the equatorial
plane of the macrocycle.
S. Kozhushkov, T. Haumann,
R. Boese, B. Knieriem, S. Scheib,
P. Bauerle, A. de Meijere* ......... 781 -783
Geminal dialkylated hydroporphyrins
are important as intermediates of the
vitamin B,, biosynthesis or as cofactors of reducing enzymes in bacteria
and plants. They can be synthesized
enantioselectively by asymmetric reduction of acylporphyrins and amide
acetal Claisen rearrangement with
transfer of chirality, and can form
complexes like 1 with metals.
Modeling the Remote-Controlled Organization of Particles in a Nanodimensional
Cavity: Synthesis and Properties of
(Et,NH),(tBuNH,),Na,[(H,O),,N;=
V,,O,,(OH),(PhPO,),]~6
s
\t
H,O.2 D M F
The Reactivity of 1,3-Butadiyne Moieties in
the “Exploding” [nIRotanes-A Crown of
Thiophenes
s\
-
2
1
D . Kusch, E. Tollner. A. Lincke,
784-787
F.-P. Montforts* .......................
A Simple, Chirogenic, Enantioselective
1
C4Ch
cw-h
Synthesis of Chlorins and Isobacteriochlorins
Contents
Umpolung of the rr-ally1 group in n-allylpalladium intermediates is possible by alkylallyl exchange with diethylzinc. The resulting nucleophilic allylzinc species can attack benzaldehyde. Thus reaction of the cyclohexenyl ester trans-1 yields cis-syn-2
selectively. This stereoselectivity can be explained with transition state structure I.
1,3-Disubstituted allyl compounds undergo analogous reactions with regio- and
stereoselectivity. L = PPh,.
+
trans-1
Y. Tamaru,* A. Tanaka,
K. Yasui, S. Goto, S. Tanaka .... 787-789
Highly Stereoselective Allylation of Benzaldehyde: Generation of a Stereochemically
Defined Allylzinc Species from a n-Allylpalladium Intermediate and Diethylzinc
cis-sym2
I
Not only aesthetic, but also structurally interesting
are the novel bridged n systems like 1with “n boat”
units. They can be synthesized by cyclization of 1,6diazacyclodeca-3,8-diyne with dihalides. Whether
the trimer 1 or a monomer or dimer forms depends
on the geometrical properties of the bridge
monomers employed (in 1 para-substituted benzene).
m
R. Gleiter,* K. Hovermann,
J. Ritter, B. Nuber .....................
‘1
789-791
Novel “n-Boat” Cage Compounds as
Potential Cryptands
,fN
1
The exothermic formation of a Ca-CO complex [Eq.(a), AHo = -25 kJmol-’1 confirms that CO can bind to a metal center without TC back donation from filled d
orbitals. In its spectroscopic properties, the calcocene-carbonyl complex resembles
“nonclassical” noble metal carbonyl complexes. Cp* = y15-C,Me,.
[CpfCa]
+ CO
(a)
[CpfCa-CO]
The asymmetric alkylation of N-propionylisoxazolidines (2a and 2b), which are
prepared by treatment of 1 a and 1 b with propionyl chloride and triethylamine,
proceeds with high diastereoselectivity, even with P-branched alkyl triflates. The
alkylated products 3 can be converted into the alcohols 4, aldehydes 5, and ketones
6 in high yields in one step with recovery of the auxiliary 1.
(+)-la:R=H
(+)-lb: R=Me
3
(-)-2a:
R=H
(-)-2b:R=Me
P. Selg, H. H. Brintzinger,*
R. A. Andersen,*
I. T. Horvath * ...........................
791 -793
Coordination of CO to the Alkaline Earth
Metallocene [(Me,C,),Ca]
A. Abiko, 0. Moriya, S. A. Filla,
S. Masamune* ...........................
793-795
Benzopyranoisoxazolidines as Chiral Auxiliaries for Asymmetric Synthesis
4 Y=CH,OH
5: Y=CHO
6: Y=COCHs
Both discotic molecules and certain linear polymers form columnar hexagonal
mesophases. Whereas the disklike structure of the macrocycle 1 is dictated by the
molecular shape, in polymer 2 it is presumably enforced by a helical folding of the
polymer’s main chain induced by the side chains (bottom right).
e
9
R-C
C-R
WOH21
‘Nn”
R-C
H. Fischer, S. S. Ghosh, P. A. Heiney,
N. C. Maliszewskyj, T. Plesnivy,
H. Ringsdorf,* M. Seitz ............ 795-798
Formation of a Hexagonal Columnar
Mesophase by N-Acylated Poly(ethy1enimine)
- + q f r ,
,c=o
’u
‘N
N’‘C-R
II
R
=
d OCIOH21
R
&
0
1
Angew. Ch6.m. In!.
2
Ed. Engl. 1995, 34, No. 7
0 VCH
VerIagsgeseNsehaJimhH, 0-69451 Wrinheim,1995
0570-OX33j95jO707-0707S10.00+ .25;0
707
Contents
Alone a tailor-made chiral cationic Lewis acid is not
sufficient to achieve high enantiomic excesses in
D i d - Alder reactions; the counterion can dramatically affect the efficiency of the chiral catalyst. Thus,
for example, the enantioselectivities reached in these
reactions in the presence of the copper complex 1
with X = SbF, as counterion are in some cases substantially greater than those with X = OSO,CF, .
$A-2:2r
D. A. Evans,* J. A. Murry, P. von Matt,
R. D. Norcross, S. J. Miller ....... 798-800
.
N-CU-N
%Me,
1
Good access to the title compounds is provided by the reaction shown below. Compound 1 reacts readily with secondary amines to give N,N-dialkylaminocyclopentadienes 2, whose Li salts can be treated, for example, with FeCI, to give the ferrocene
derivatives 3.
C,-Symmetric Cationic Copper(I1) Complexes as Chiral Lewis Acids: Counterion
Effects in the Enantioselective Diels-Alder
Reaction**
H. Plenio,* D. Burth ................. 800-803
Aminocyclopentadienes, Aminoferrocenes,
and Aminocobaltocenes
3
1
2
An eficient solid-phase synthesis of glycopeptides is achieved with the new anchor
HYCRON, which combines an allylic ester with the flexible, solubilizing triethyleneglycol spacer. Acid- and base-stability of the allylic anchor enables both
Fmoc and Boc strategies to be used. The partially protected glycopeptides can be
cleaved from the support by Pdo catalysis under virtually neutral conditions in high
yields (about 95 %) and purity ( > 95 %). AMPS = aminomethylpolystyrene.
li
A Novel Allylic Anchor for Solid-Phase
Synthesis-Synthesis of Protected and Unprotected 0-Clycosylated Mucin-Type
Glycopeptides
B-Ala-AMPS
Hexaethynyll3jradiaIene (1 a) is isoelectronic and
isosteric with the known hexacyano[3]radialene and
a molecular precursor for a two-dimensional all-carbon network. The hexakis(trimethylsily1) derivative
1 b was now prepared by addition of tetrachlorocyclopropene to deprotonated 1,5-bis(trimethylsilyl)penta-l,4-diyne, followed by oxidation, and was
characterized by X-ray crystallography. In solution,
1b shows an unexpected purple-red color and is reduced in two reversible one-electron steps to the
violet radical anion 1b' and dianion 1 b2-.
A facile route provides the title compound 1 in only
a few steps starting from bromopentafluorobenzene. Borane 1 is a very reactive hydroborating
agent for a range of alkenes and alkynes. Reactions
with unsymmetrical substrates display excellent regioselectivity, and interesting selectivities with silicon-containing substrates are rationalized by electronic effects.
708
803-805
J
Y
HYCRON
0. Seitz, H. Kunz* ....................
Q VCH Ver~ugsg~si,lls~liaff
mbH. D-69451 Weinhdtn, 1995
T. Lange, V. Gramlich, W. Amrein,
F. Diederich,* M. Gross, C. Boudon,
J.-P. Gisselbrecht .......................
805-809
R
Hexakis(trimethylsilylethynyl)[3]radialene :
A Carbon-Rich Chromophore with Unusual Electronic Properties
R
R
laR=H
1b R = Me3Si
r
F
1
D. J. Parks, R. E. von H. Spence,
W. E. Piers* ...............................
809-811
Bis(pentafluoropheny1)borane: Synthesis,
Properties, and Hydroboration Chemistry
of a Highly Electrophilic Borane Reagent
0570-0833/95/0707-0708$ 10.00+ .25/0
Angekc. Chem. Int. Ed. Engi. 1995, 34, N o . 7
Contents
The direct sulfonation of arylphosphanes with
H,SO,/SO,/boric acid offers numerous advantages,
the most significant being that P oxidation is largely
avoided. In addition, selective sulfonation is possible. The products, for example 1, are water-soluble
and interesting with respect to two-phase catalysis.
Ar = C,H,-in-SO,Na.
W. A. Herrmann,* G. P. Albanese,
R. B. Manetsberger,* P. Lappe,
H. Bahrmann .............................
811 -813
PAr,
NaOaS
Na03S
PAr,
'
R. Deissenberger, S. Kohler. F. Ames,
K. Eberhardt, N. Erdmann, H. Funk,
G. Herrmann, H.-J. Kluge,
M. Nunnemann, G . Passler, J. Riegel,
F. Scheerer, N. Trautmann,*
E-J. Urban .................................
814-815
By multistep resonance ionization with lasers, followed by mass spectrometry, the first ionization potential of neutral atoms can be measured with quantities of only about one nanogram. The ionization
potentials of americium (5.9736(3) eV) and of curium (5.9914(2) eV) were thus determined for the first
time. The figure on the right shows a plot of the
number of ions N versus the total photon energy E,,,
of three laser beams, which are essential for the experiment. The arrow points to the ionization
threshold.
First Determination of the Ionization
Potential of Americium and Curium
Self-diffusion coefficients of a series of polycyclic charged systems and their parent
compounds were measured by using the PGSE NMR method. These data suggest
that the dianions of naphthacene 2 and pyracylene 3 may exist as dimers with
sandwich structure, just like the lithium salt of the tetraanion of corannulene 1.
@
@
2
1
New Process for the Sulfonation of Phosphane Ligands for Catalysts
Y. Cohen,* A. Ayalon ................ 816-818
Self-Diffusion of Charged Polycyclic
Systems and Their Parent Compounds:
A PGSE NMR Study
3
The ambiphilic reactivity exhibited by the silicon
compound 1 contrasts the behavior of neutral
silanes and simple silyl anions. This reactivtiy is an
indication of silylenoid character, which can be accounted for by the two limiting electronic structures
l a and 1 b.
A new three-dimensional coordination network with
cubic symmetry is displayed by the structure of 1
(shown on the right). Compound 1 is obtained from
tri(4-pyridy1)triazine ligands (tpt) and HgZ* ions,
and has a system of interconnected spacious cavities
which are occupied by large numbers of solvent molecules and counterions. The coordination sphere of
the Hg center is formed by six pyridine substituents,
which is very rare for complexes.
.-*
Ph2Si
K . Tamao,* A. Kawachi ............ 818-820
0
,ti+
<
Ph,Si'Li
The Chemistry of Silylenoids: Preparation
and Reactivity of (Alkoxysily1)lithium
Compounds
0-1-BU
&u
'
la
lb
S. R. Batten, B. F. Hoskins,
R. Robson * ...............................
820-822
2,4,6-Tri(Cpyridyl)-l,3,5-triazineas a
\'
3-Connecting Building Block for
Infinite Nets
'a-
[Hg(tpt)J(C10,)2 ' 6CZHzCIa 1
"'
Complex 2 is formed by two discrete ions which originate during hydrogenolysis of
1 according to Equation (a). The cation is dinuclear with three bridging hydrido
ligands. The mixed-valent anion of 2 is also dinuclear and contains two bridging
nitrido moieties, which cannot be the product of the hydrogenolysis of N-Si bonds
since silanes are not formed in the reaction.
+
4 [((Me,SijZN/V{CH,(SiMe,)NSiMe,)(PMe3)] 5.5H2 + N,
I
-
P. Berno, S. Gambarotta* ......... 822-824
Reaction of a Vanadium(iI1) Amide with
H,: Isolation and Characterization of a
Polynuclear Mixed-Valence PolyhydridoNitrido Complex
(a)
~ ~ ~ ~ ~ 3 ~ ~ 3 V ~ z ~ ~ - ~ ~ , I " : ~ ~ ~ ~ ,+S4j(Me,Si),NH
)2~12V),(L-~~zl~
2
A n p w . Chivn. I n l . Ell. Engl. 1995, 34, No. 7
(0VCH
Verlugsgrseii.schuji m h f f , 0-69451 Weinheim, 1995
+
0570-083319510707-0709 3 10.00 .25/0
709
Contents
The stable borylene-bridged Mn, complexes 1 and 2
are formed in the reaction of K[($-C,H,R)Mn(SiMePh,)(CO),]
with the diboranes(4)
B2X,C1,. The mechanism of formation still remains
to be clarified. The molecular structure of 1 (R = H)
shows similarities with dimetallacyclopropane
derivatives.
0
0
H. Braunschweig,*
T. Wagner ..................................
825-826
Synthesis and Structure of the First Transition Metal Borylene Complexes
X
1 : R = H,Me; X = NMe,
2 : R = Me;X = f8u
Corrigenda
826
* Author to whom correspondence should be addressed
BOOKS
Linear and Nonlinear Optical Properties of Molecules
Modern Medicinal Chemistry
*
- G. H. Wagniere
J. B. Taylor, P. D. Kennewell
Keyword Index 830
C. D.Bain ..........................................
827
A . Giannis ..........................................
828
Author Index 831
Preview 832
Chemistry-A European Journal may be found after page 832 with its
own table of contents and separate pagination.
710
(p VCH Verlagsgesellschufi mbH, 0-69451 Weinheim, 1995
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Angew. Chem. Inr. Ed. Engl. 1995, 34, No. 7